How do I buy & sell Crypto on OKX?

Hello there, I'm new to the world of cryptocurrency and I'm interested in learning how to buy and sell on OKX. Could you please guide me through the process step by step? I'm particularly curious about how to create an account, fund it, choose the right cryptocurrency to invest in, and finally, how to sell my holdings when the time is right. Also, if there are any security measures I should be aware of while trading on OKX, I'd appreciate it if you could highlight those as well. Thank you in advance for your help!